The field of this disclosure relates generally to airfoils and, more particularly, to a gas turbine engine airfoil and a method of fabricating the same.
Most known gas turbine engines have a compressor system, a combustion system, and a turbine system. During operation, compressed air from the compressor system is directed into the combustion system, and the compressed air is mixed with fuel and ignited in the combustion system to generate a flow of combustion gases. The flow of combustion gases is directed into the turbine system, which includes at least one stage having an annular stator followed by an annular rotor. The stator has a row of stator airfoils (i.e., stator vanes), and the rotor has a row of rotor airfoils (i.e., rotor blades). In this manner, the combustion gases flow through the stator vanes and over the rotor blades to spin the rotor, which generates shaft power for the compressor system or a generator.
It is known that increasing the temperature associated with the combustion process can yield an increase in the combustion gas temperature and, therefore, an increase in engine operating efficiency. It is also known that increasing the combustion gas temperature can induce significant thermal stresses on the airfoils of the turbine system, thereby decreasing the useful life of the turbine airfoils. As a result, at least some known turbine airfoils are cooled via a cooling process that discharges cooling air from apertures of the airfoils, which enables the airfoils to better withstand a temperature increase in the combustion gas flow. However, it is also known that discharging cooling air into the combustion gas flow can lower the temperature of the combustion gases, thereby detracting from the operating efficiencies that were to be gained via the temperature increase in the combustion process. It would be useful, therefore, to provide airfoils that can be cooled in a manner that increases the useful life of the airfoils with less affect on engine operating efficiency.